View Full Version : Sodium Phosphate

09-16-2006, 11:17 AM
Do any of you use this?

It is recommended in Joe Friel's Training Bible...

My partner and I have both "tested" it this last week to make sure it doesn't upset our stomachs. We both seem fine.

We are going to try loading with it - the 3 day regimen (4 grams per day) in a week and a half just prior to a TT race in a couple of weeks.

It is meant to help the haemoglobin release oxygen in the muscle, which effectively means that the muscles are able to operate at aerobically at higher speeds and power outputs than usual.

Some studies have shown that it effectively raises the lactate threshold by up to 10%. The gains from Sodium Phosphate loading are supposedly still there after a week.

What do you think?
Do any of you use it?
Is it effective or just a placebo?
And to the purists out there... is this bordering on drug cheating?

Squirrel 2
09-17-2006, 02:59 AM
are you sure you want to do this?


09-17-2006, 05:53 AM
I consulted my husband, who is a chemist, and in his non-medical opinion did not think taking sodium phosphate for this purpose was a good idea. Check with a doctor or pharmacist.

09-17-2006, 05:58 AM
Is there something else you could do instead? A little extra sleep, a massage or two?

Messing with the acid/base chemistry of your blood isn't going to help functional oxy much. Remember, if the hemoglobin is releasing oxy easily, it's equally poorly transporting oxygen. Like taking the shoelaces out of your shoes because it's so much easier to get them on and off then, but can you run well without shoelaces holding your shoes on?

I have a fabulous host of neurological problems because my body screws up the acid-base balance of my blood all by itself. The thought that it takes a week or more for you to recover after dosing yourself with sodium phosphate is quite chilling.

Trust me, you don't want what I've got. And yes, I think that could be considered cheating if it actually worked. And dangerous either way.

09-17-2006, 07:03 AM
Why would you want to take additional sodium and phosphate?

your diet probably contains enough sodium and phosphate and from a biochemical point of view, these are not required in the release of oxygen in the muscles. Can you provide a link to said study?

Loading with a water soluble salt makes very little sense, as you will just excrete any excess.

09-17-2006, 11:18 AM
Thanks for your concern ladies.

I am not too worried about it, as Friel recommends it as one of the "best kept secrets in cycling". In the same chapter he talks about other legal performance enhancers like caffiene (which many of us here at TE use). Every other bit of advice and observation of Friel's I (and other friends who have his books) have followed has been useful, sound and improved my fitness - both physical and mental.

It is legal Knotted, but I was interested to see how many might think of it as cheating - for me the lines are thin. I use caffiene in races - I take it an hour before I will need it, as it is most effective an hour after being consumed. Is this different? I dont know. Its a performance enhancer and not naturally found in the body... should it be disallowed?

Like creatine, found naturally, can be consumed naturally or over the counter? Is it bordering that thin line? You can eat huge quantities of red meat to load with it, or take it as a more convenient powder - the perception out there is that it "builds muscle" but many studies show that used judiciously it helps with recovery... a close friend has been using that as a powder and has found his muscles feel better and recover more quickly.

I hear your concerns Knotted, and I am listening. I have followed how health impacts on several women here (including you). I appreciate your concerns.

Alpine... Friel cites several studies in his little blurb about it. The link of Squirrel's is 5 years old - maybe I need to find some more specific recent studies - that link is about use for constipation, not sporting related.

I will take your words under advisement and keep researching til next weeks "D-Day".

I would be interested in any other opinions, links, critiques.

If you don't wanna talk about it in public, please PM me.

I am still considering doing this unless I can find compelling evidence to stay away. You gals seem to collectively see everything there is and I value your input and opinions.

Thanks again for your responses thus far.


09-17-2006, 02:31 PM
The way I interpreted Squirrel's "are you sure you want to do this?" question was that if sodium phosphate can be used to relieve constipation, and you're not constipated, wouldn't that cause some diarrhea issues that are not all that easily handled while competing in a bike race?

09-17-2006, 04:59 PM
RoadRaven, I would be really interested in the references you have regarding this supposed benefit of sodium phosphate.

My only knowledge of the use of sodium phosphate in relation to oxygen diffusion comes from its use as a buffering agent when doing experiments on isolated muscle cells. If that is the basis this guy is claiming for the use of sodium phosphate as a supplement, then it is based on poor science and not only is it one of the best kept secrets in cycling, it is one of the best kept secrets in medical science.

09-18-2006, 10:27 AM
DivingBiker (do you really? dive on the bike I mean? your nic conjures up some funny images... I'm guessing you "dive" down hillsides?) your post cracked me up - I hadn't read Squirrel's post that way - of course! That is an important consideration! It didn't seem to have that effect on either of us last week when we 'tested' it on our stomachs. Fingers (and legs?) crossed if we load next week with it.

Matagi... I did a quick google search and found the following bits I will paste below. At the weekend, I'll type in what Friel says in his book along with the studies he refers to...

09-18-2006, 10:30 AM
Race Day Nutrition by Rich Strauss (March 2005)

This article was in both these places. This excerpt below was taken from the sub-headed section called “Rich’s bag of Tricks”, he also outlines the nutrition intake (including sodium phosphate) for the week before an Ironman.

Loading with sodium phosphate (PhosFuel). Sodium phosphate acts as an acid buffer, reduces the build up of lactic acid, and thus increases the body's tolerance for lactic acid. [It also enhances offloading of oxygen from hemoglobin to muscle tissue. – Jeff Roberts]

09-18-2006, 10:32 AM
Forn & Fitness Q & A page (May 2005)

Sodium phosphate
Any thoughts about sodium phosphate loading prior to a few races per season? Joe Friel has a bit on it in the Cyclist's Training Bible and it's sold as 'Race Day Boost' by e-caps.com. I recently tried it, but it's hard to know if it really made any difference. I've read some of the research and it seems pretty equivocal, but I wondered if you had any thoughts.
Steve Smith
I have no idea where JF's loading regimen originates from as there is no research to substantiate his loading protocol (which, if I recall correctly, uses a very low dose every day). Although at first it appears that phosphate loading is equivocal, it appears that many or all of the studies that used tribasic sodium phosphate showed a significant ergogenic effect. Currently, we are unable to explain why it is only this phosphate that appears to work. In our study (Folland, Stern & Brickley, 2001, A, CJAP) (see http://cyclecoach.com/articles?article=Phosphates&ext=.htm) we found an ~8% increase in power output compared to a control and placebo trial.
We used 4 x 1g/day for six days. This led to a reduction in time during a 10-mile TT of ~ 40-secs. Currently, no one has determined the exact mechanism which improves performance via phosphate loading (although there are a couple of hypothesis) and it hasn't definitely been determined that it always works.
It's important to note that phosphate loading isn't for everyone, and in some people it can cause instantaneous vomiting or diarrhoea. With this in mind, and with all new supplements and sports drinks etc you should always try these out in training first and not directly prior to, or during a race. It is strictly recommended that phosphate is not taken on a regular basis. Some research suggests that it may cause calcium to be leached from the bones if consumed regularly. Current advice is to not take it more than four times per year.

09-18-2006, 10:34 AM
Comments from CyclingForums archive

Duckwash said: sodium phosphate and sodium bicarb loading are both legal and work by buffering the lactic acid produced in your muscles

if you plan on using sodium phosphate make sure you try it out a few weeks before an event because from memory you need fairly big doses and it might upset your stomach

as for supply you can get it from some sports shops or look ub a lab supply place and buy analytical grade (might be pricey tho)

Zaskar said: Here is more info on it, i just ordered some for a mountain TT i have this month. i want to knock off 1 min 15 secounds off my time i hope this helps!

RACE DAY BOOST contains one of the most potent legal ergogenics available for competition. In the most extensive study to date on the key ingredient in RACE DAY BOOST, subjects in a 40K time trial netted a whopping 8% improvement in performance time! The simple formula belies its profound effectiveness, supplying your body with what it needs to increase cellular energy production and buffer performance-robbing lactic acid. When one of your most important races of the season is four days away, a loading dose of RACE DAY BOOST can make a remarkably noticeable difference in your race performance.

Gooders said: when you buy it a fact sheet is provided on loading.

from what I've read you can only use 3-4 times per year due to the potenial adverse affect calcium depletion caused by sodium phosphate. Might be beneficial to take a low dose mineral supplement during loading.

Also I've found it did give me the trots the first time I used it. Since I now load over two weeks. The first week slowly introduce the phosphate - 1g x 1, then a days break, then 1g x 2, then a days break....etc until you are 1g x 4. Then load for 4 days.....some can tolerate it better than others though.

hope this helps.

Ric_stern said: I've read positive results about using a one off Sodium Citrate loading:

Oopik et al. (2003) a 5km run 30" faster (2.5%) in runners completing the task in 19-mins.

Potteiger et al. (1996) a 30km time trial was 103" faster (2.89%) in cyclists completing it in approx 59mins.

McNaughton (1990) a 1-minute sprint had Peak power up 215w (20%) an total work up 8.5KJ (23%).

Have you experience using this as an ergogenic aid and can it be combined with Sodium Phosphate.....or not really worth considering.


i have no experience with citrate loading


09-18-2006, 10:36 AM
And the last of these four eExcerpts - this is the oldest and is from 2000 and written by Joe Friel himself...

ETips Newsletter, Vol3 No7 July 2000

How to Load with Sodium Phosphate
Q: I was thinking of trying sodium phosphate, as you suggest in your book. But after buying some Twinlabs Phos Fuel I noticed that the bottle suggests loading for three days with four grams per day instead of your 19-day procedure. Today is the 19th day out from the first of two races that I would like to peak for. So I was just wondering about the discrepancy between your loading plan and Twin Lab's. - J.A.
A: I'd suggest not using sodium phosphate if the race you're talking about is an A-priority. It should be tried in training or before a C-priority race first. It could be that you don't handle it very well and this might lead to a poor race. When it comes to tolerance of dietary supplements there is a lot of individual variance. In regards to how to use it, I've found that many athletes have upset stomachs when using sodium phosphate so that's why I recommended the longer loading period in my book. If it doesn't cause an upset stomach then the shorter loading period as described on the label is fine. But you need to discover this in training early in the season. - Joe Friel

09-18-2006, 11:03 AM
whoops... meant to add...

BikingMom... I have checked with 3 chemists, the health shop and a doctor.

Doctor hadn't heard of it, chemists hadn't heard of it, health shop had a little info and was interested as she has a few cyclists through so I photocopied Joe Friel's bits for her and have said I will go in after race and let her know how/if it worked.

I am going to email a couple of the health fitness lecturers at work today, and see if they have heard of it and what they think...

09-18-2006, 12:22 PM
I copied your question over to RBR, here's what the guys say:


09-18-2006, 01:33 PM
chemists hadn't heard of it

Chemists did not know what NaPO4 was? Now that is a terrifying thought to me. I am hoping the chemists you spoke with had not heard of it used to buffer lactic acid in the muscles, rather than not knowing what NaPO4 was.

For what it is worth, I do not have any knowledge of whether or not this will work or if it is harmful to use. Sodium and Phosophorus are consumed by us on a daily basis, that is the extent on my knowledge. I am a SAHM with a masters in Physics, so I have far less knowledge on this topic than others.

09-18-2006, 02:01 PM
I thought the latest studies found that lactic acid is a fuel?

09-18-2006, 04:31 PM
Thanks Snap... I went and had a look, quite a range of thoughts there - from "total cr*p" to "give it a go". I'll keep an eye on it and see if anything else is said. Can you say thanks to everyone for there input?

BikingMom - I did mean they hadn't heard of it as a sports performance enhancer. :p LOL - your post made me smile! Some people think this country is backward cause we're so little and far away... but trust me, our chemists have heard of NaPO4!!! :D :rolleyes: :D

Knotted, you're right. For a long time lactic acid (LA) was touted as an ogre, a demon, a menace. However, more recent studies have shown that lactic acid actually does help - but, your muscles reach a point when they can only utilise so much LA and then it becomes a burden.
So the trick is to increase your LT so you can use the LA for longer.

So my current training involves some rides where I work at or above my LT and this helps my body to get used to working there and to tolerate the LT for longer.

In April, my LT was measured in a sports science clinic at 152bpm.
In May, after specific training it was remeasured again, this time at 156bpm.

I was supposed to get it measured again in August, but the machine broke and the parts come from the USA and they are still waiting on them.
I am guessing that my LT (based on TTs I have done) is sitting at about 162bpm now.
With a max HR of 184bpm, training can lift my LT even further.

The Sodium Phosphate is supposed to enhance the muscles performance which effectively lifts there ability to perform above the LT. In a TT you sit at or just above your LT for the whole race. Anything to help - even if i don't go faster but have less pain cause the muscles aren't working as hard - well that would be a bonus too.

09-23-2006, 10:15 AM
Reference: Friel, J. (2003). The cyclist’s training bible (3rd ed). Boulder, Colarado: Velopress (p.220-221)

(Chapter 16 “Fuel” – also found in Chpter 16; Protein, carbohydrates, fat, water, antioxidant supplements, ergogenic aids, branched-chain amino acids, medium-chain triglycerides, creatine, caffiene, glycerol)

The German Army used sodium phosphate in WWI, and even in the 1930s German atheletes knew of its worth. It has not received a great deal of publicity in recent years, though some atheletes have known about it for years but kept the secret.

Sodium phosphate has the potential to improve a 40k time trial significantly, alloq you to hang on when the pace would normally have you off the back and make high-intensity efforts feel much easier.

In 1983, researchers working with elite runners found that sodium phosphate increased aeobic capacity by 9 percent and improved ventalattory threshold (like lactate threshold) by 12 percent. A more recent study of cyclists in Florida showed showed that using phosphate improved low-level endurance times significantly, lowered 40k time trial times by 8 percent, and raised lactate threshold by 10 percent, while lowering perceived effort. These results seem a bit extreme, but there is limited research on sodium phosphate.

It appears to produce benefits by causing the hemoglobin in the red blood cells to completely unload their stores of oxygen at the muscle. A greater supply of oxygen allows the muscles to operate aerobically at higher speeds and power outputs that would normally cause an anaerobic state.

The next/last three paragraphs in this section are about how to load with it, possible symptoms if your body does not like it and warnings to try it out well before you need it.

References at the end of the chapter that appear to support this section:

Altering cardiorespiatory fitness. (1986). Sports Medicine 3, no.5, p. 346-356

Anderson, O. (1996) Carbs, creatine and phosphate: If the king had used these uppers he’d still be around today. Running Research News 12, no.3, p.1-4

Cade, R. (1984). Effects of phosphate loading on 2,3-diphosphoglycerate and maximal oxygen uptake. Medicine and Science in Sports and Exercise 16, no.3, p.263-268

Kreider, R.B. (1990). Effects of phosphate loading on oxygen uptake, ventilatory anaerobic threshold, and run performance. Medicine and Science in Sports and Exercise 22, no.2, p.250-256

Kreider, R.B. (1992). Effects of phosphate loading on metabolic and myocardial responses to maximal and endurance exercise. International Journal of Sports Nutrition 2, no.1, p.20-47

Stewart, I. (1990). Phosphate loading and the effects on VO2max in trained cyclists. Research Quarterly for Exercise and Sport 61, no.1, p.80-84

09-23-2006, 11:30 AM
Hey there Matagi - trust those references above are useful - I have still been unable to find anything more recent...

Well... tomorrow is D-Day - I am going to try this stuff out, I'll come back and give you a report on whether I think it helped or not. I have decided I see it as no worse than using caffeine which is an introduced substance to our bodies - both sodium and phosphate are found in our bodies naturally and all I am doing is increasing those levels for short term.

I see it as similar to taking extra calcium, or creatine, or iron, or phosphorous, or myriad other bits found in supplements or in the "gu" you take to help you during a race or a long ride - they all boost performance and endurance and fitness. I take none of these except calcium occasionally and caffiene as part of a day to day "addiction". I use gu on rides of over 2 hours duration - none of my rides are long enough to warrent their use. I am not taking this supplement (NaPO4) lightly, and do not take even vitimins on a regular basis - so am not a "performance enhancer junkie".

Still, I am very interested in what you may have to say - please be candid because I value all your input, both negative and positive critique.

I will start tomorrow (Monday) with low doses to get my tum prepared, and then the loading begins on my Wednesday. The TT is on Saturday...

09-23-2006, 12:24 PM
Some people think this country is backward cause we're so little and far away:D :rolleyes: :D

LOL - lets just keep it that way...dont want the world to know what a great and beautiful country yours is or I will have to fight the crowds when I drop over on holidays from Aust.:D :D

Good luck and let us know how it all works out for you.


09-28-2006, 11:21 AM
You a Melissa fan?
Just noticed your sig... have you changed that recently? I don't know how I could have missed it!
She is such an awesome rocker! I wish wish wish I could go to one of her concerts, but unless she comes to NZ I guess I will have to settle for DVDs and surround sound.

Well, last day of loading today - have been taking 4grams of this stuff Wednesday, Thursday and Friday.

So far no tummy probs like Squirrel and DB wondered about... except that I 'normally' go 1-2 times a day, and this week am 'going' 3-4 times a day, but its normal, just more frequent.

Still not sure if I am doing the right thing, but if this isn't right then surely having coffee or a "power drink" before a race isn't either...

I'm still interested in your opinions, even if they don't support what I have done. I was really hopoing for more feedback before this week began.

Anyway, race tomorrow, we'll see what happens.

09-28-2006, 11:50 AM
Have a great race RoadRaven!!! I'll be watching the thread to see how it went and if you feel the Sodium Phosphate helped.

09-28-2006, 11:58 AM
You a Melissa fan?
Just noticed your sig... have you changed that recently? I don't know how I could have missed it!
She is such an awesome rocker! I wish wish wish I could go to one of her concerts, but unless she comes to NZ I guess I will have to settle for DVDs and surround sound.

Yep Im a fan. I changed my sig line a few months ago. I love this song.:)

Good Luck for Saturday.

09-29-2006, 10:02 AM
Lactic acid is NOT a fuel. it makes zero sense biochemically. I have discussed this elsewhere on this forum.

09-29-2006, 11:53 AM
Alpine, I didn't say lactic acid was a fuel... I said it was seen as something to be avoided, but as people have come to understand how it works and builds up, people can train to be able to perform despite its presence and within tolerance levels...

Do you have any understanding of NaPO4? I would value your opinion on this, just as I have your clear explainations of LA in other threads.

Thanks for your good wishes Artisan and Trek... 6 hours til kick-off (or should that be "wheel-turn"?)

09-29-2006, 12:29 PM
Hi Raven,

you did not bue Knotted repeated the statement about Lactate. About the phosphate, well I was skeptical but I searched pubmed:
Since the 1930s, scientists have attempted to determine if increasing the body's ability to buffer metabolic acids will enhance physical performance. The buffer of major interest has been bicarbonate; to a lesser degree, citrate and phosphate salts have been investigated. In theory, the buffers facilitate performance by decreasing the accumulation of hydrogen ions that would otherwise presumably inhibit glycolysis and interfere with energy production or impair cross-bridge formation between myofilaments and thereby reduce force production. Literature findings indicate variable results, but overall it appears that bicarbonate salts taken at dosages of 0.3 g.kg-1 may improve performance during repeated sprints or at the end of a progressively more intense exercise test. Athletes are advised of potential ill effects of bicarbonate ingestion, such as gastrointestinal distress. Prior to applying the agents in a competitive setting, athletes should test the effects of buffers on performance during training sessions and consider the sport governing body's stand on buffer usage.

from Pubmed (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=7550253&query_hl=3&itool=pubmed_DocSum)

hmm... the question is where are the "loaded" buffer salts stored. in the intestine perhaps? and if so, when is the optimal timepoint to take them?

OTOH, I wonder if this really makes a difference for the "amateurs" among us. there are so many other factors playing into your performance on day X, aren't there...

09-29-2006, 12:51 PM
Thanks Alpine... appreciate your reflection here

For me, as an enthusiastic amateaur am just interested to see if it makes a difference to my LT or to the preceived ease or pain I have in completing an intense race.

For others trialling this at a much higher level of racing I guess it will remain to be seen whether it can assist in precious seconds.

As you say - so many variables...
At the moment the weather is calm and mild - what if i battle a wind this afternoon?

How I perform toady will be different to how I would perform in 2 weeks time when I will have my period.

I have taken notes of food consumption for the past few days... and if I feel NaPO4 makes a difference today, I will try and replicate the same race (food, pre-race week rides, rest etc) without NaPO4 in a few weeks, and then again with another loading period.

Its about as scientific as I can get. I'll get back here this evening or tomorrow and give my opinion as a "user".

09-30-2006, 11:00 AM
Did it help?
I think so… this is the first TT I have completed where I was able to sit at or above my LT for almost the entire ride.

My average HR for the race was 162bpm. My last measured LT was 159bpm. I am assuming that an average of 162bpm is my new LT resulting from specific training and not as a result of taking NaPO4.

However, the fact that I consistently had my HR sitting around 168-175bpm makes me wonder if that was the Sodium Phosphate, because although my training has tried to be specific, I have never ridden that high for so long before.

No stomach upsets (apart from being “more” regular) and no other side effects to my knowledge.

I would try this again, but I did a few things wrong in my pre-race week and on the day, so I have to get those things right too (see Racing Report forum).

03-20-2007, 09:48 AM
Well, last TT of the season this coming Saturday.

I have some Sodium Phosphate leftover from last year's "test", and have decided to use it up this week.
I did a TT on Sunday which gives me a good indication of my current performance level.

So I'll start loading today (4 grams per day for the 3 days before race day) and see if there is a more discernable difference than my last "I think so/maybe" conclusion.

I'll keep you posted.

03-26-2007, 11:09 AM
Well... I don't think I'll bother again... it didn't seem to make a huge difference. I think a caffiene drink half and hour before the start of the race has more impact on my system... it was an interesting experiment.

I think it made the race easier to get through but I don't think it increased my performance in terms of time. I did a PB, but I was expecting to anyways...

It was interesting to be your guineapig, ladies... but my money is better spent elsewhere than these tabs.

01-11-2008, 10:51 AM
Just going to resurrect this...

I have increased my performance after a long plateau.
I was given a bunch of vitimins etc from a family friend who was clearing out her cupboard and having tossed about half of them due to being past use-by date or just not looking "fresh" so moisture must have got in...

However, several bottles/jars of bits and pieces - one of which a complete unopened jar (80tabs) of Sodium Phosphate.

So I figure - why not? I have a good idea of where I am at, will be time-trialling a course this coming Thursday that I raced only 4 weeks previously.

As I have said earlier in this thread, it is legal, these are naturally occuring minerals in the body - caffiene isn't and yet it is also legal...

Although this student research was highlighted in another forum

... and states "Repeated measures analysis of variance (P< 0.05) indicated no significant effects of sodium phosphate supplementation in contrast to the placebo treatment for VO2max or blood lactate. In conclusion, our data suggest that NaPO4 is an ineffective supplement when used to enhance endurance performance."
... I am still going to give this a go.

So, the race is Thursday, this means I take some low doses on Sunday and Monday, and then load Tuesday, Wednesday, Thursday and race Thursday evening...

I am interested to know if anyone else here has tried this out yet. Even a PM if you don't want to disclose in this thread...

And I am still interested in your opinions about this - either way - whether you are interested/enthusiastic or whether you think this borders on/is cheating...

Everything welcome, I will not take offence

01-11-2008, 10:54 AM
In addition to my above post...

This was posted at RoadBikeReview by Zoikz in 2006...

One of the central limitations of sports medicine research is generally these studies are done on very small samples. Because of this they have very little power, ie. their conclusions are really not statistically significant. When you look at any given topic there are multiple small studies with differing conclusions. Sodium phosphate is typical, there are studies on either side; benefit, no benefit.
To be fair these studies are generally poorly funded and technically difficult to perform. It would be very, very difficult to conduct the large placebo based randomized trials everyone in medicine loves.
One word of warning though, look at who funds these different projects. Often these research studies are conducted by researchers or labs with a vested intereest in the product they are assessing. Accelerade is certainly a good example of bad science conducted by biased researchers.
My take on phosphate is it probably won't hurt so give it a shot if you want. Doubt it does much of anything though.