The popularity of testosterone boosters is ever-increasing, and for good reason.

These supplements put your testosterone production into high gear, raise your libido, and enhance your quality of life as a man.

This time around, we’re taking a look at RSP Prime T. A testosterone booster that’s been around for a while.

In our detailed RSP Prime T review, we’ll inspect its side effects, ingredients, benefits, and more.

Prime T aims to help you:

  • Maintain high testosterone levels
  • Improve lean muscle mass
  • Enhance libido

It has some solid ingredients, such as fenugreek, DAA, and vitamin D. However, the dosages could be better, and there’s also a problem with too few daily servings. Which can affect the results you get from this T booster.

Sit tight, we’ll explain everything in detail below. So you can determine if RSP Prime T is the right choice for you.

Who Makes RSP Prime T

As you could guess by the title of this review, Prime T is the name of the supplement, and RSP Nutrition is the company behind it.

RSP Nutrition was started back in 2008 by two former collegiate athletes. They weren’t happy with the supplement market at the time, so they decided to start their own supplement line.

Fast forward to today, they’ve grown into a renowned company that offers a variety of products. This includes pre workouts, protein shakes, and amino acids. Prime T is their flagship testosterone booster.

Let’s see if it can give other top-rated testosterone boosters a run for their money.

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The benefits of RSP Prime T include:

  • Supports men’s virility
  • Increases strength and lean muscle
  • Supports libido
  • Promotes estrogen balance
  • Supports prostate health

By looking at the benefits, it’s clear RSP Prime T is intended to be an all-around men’s health supplement. Boosting not just testosterone but also other aspects of ‘masculinity,’ if you will.

Now, all of this sounds great in theory.

But what does really happen when you take this testosterone booster?

Let’s check the ingredients to find out:


This is where it gets interesting for RSP Prime T. It contains some great ingredients which are scientifically backed up to support healthy testosterone levels and libido.

But it’s not all sunshine and rainbows, as Stallone would say. Prime T contains 250mg of DIM, which in some studies has been shown to increase estrogen activity, instead of decreasing it. The science still isn’t fully clear on the optimal DIM dosage. As a result, we suggest being careful with this ingredient until more evidence comes out.

Shall we look closer?

RSP Prime-T ingredients

Vitamin D

If you’re deficient in vitamin D, supplementing with it can bring your testosterone levels back to normal. The dose in Prime T is 3000IU per 4 capsules. The strongest testosterone boosters on the market offer even more than that – 4000IU. This is for a good reason; research that tested vitamin D’s effects on testosterone used doses of 3,332IU or higher. We don’t know whether the lower doses like the one in RSP Prime T will have the same benefits but is very close. (1)

Vitamin B3

Vitamin B3 supports your energy metabolism. It’s more of an ingredient for a fat burner than a testosterone booster. But hey, who doesn’t want to drop a few unwanted pounds? (2)


Folate supports muscle recovery, but only if you’re deficient in it. Most people who eat a diet containing animal foods aren’t deficient. (3)

Vitamin B12

Similar to folate, this vitamin can only help you build muscle if you’re deficient in it. Usually, the only people who could be deficient in B12 are elderly and vegans. (4)


Zinc is a staple ingredient in testosterone boosters because it works. It’s needed by your body for countless functions, including testosterone production. In fact, you could have problems with low T if you lack zinc in your diet. The issue here is, RSP Prime T uses a relatively weak dose of zinc – 12mg. The optimal zinc dose for boosting testosterone is somewhere around 20mg per day. (5)

D-Aspartic Acid

D-Aspartic Acid helps temporarily boost testosterone levels. It doesn’t appear to work long-term though. RSP Prime T delivers 3200 mg of this ingredient, which is the optimal dosage according to research. (6)

Fenugreek Extract

When used in conjunction with D-Aspartic Acid, fenugreek helps support your male hormone. It won’t raise testosterone levels above their normal but will help if you suffer from low T. Fenugreek extract can also enhance your libido and improve glucose metabolism. (7)

Maca Root Extract

Maca won’t do much for your testosterone, but some people find it increases their libido and sex drive. (8)

DIM (3,3,’-Diindolylmethane)

This is the first controversial ingredient in RSP Prime T. See, DIM is usually found in broccoli and cauliflower in small amounts. It is a byproduct of Indole-3-Carbinol. When you consume I3C, your body naturally breaks it down to DIM and other molecules that are beneficial for your testosterone and overall health. However, taking DIM in isolation can actually have the opposite effect – increasing your estrogen levels, which can potentially lead to reduced testosterone. (9, 10)

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Additionally, separate studies using different amounts of DIM have seen completely different results; in some studies, DIM increased estrogen levels, but in others, it decreased the female hormone. (9, 11)

So what can you conclude from this? So far, certain studies point that taking DIM in isolation may not be the best idea for testosterone and overall health. Instead, it’s better to consume Indole-3-Carbinol, which naturally breaks down into DIM and many other beneficial molecules, just like the nature intended. There are two ways you can get Indole-3-Carbinol: through cruciferous vegetables, or by taking supplements that use this safe and natural compound.

Safed Musli Extract

Safed Musli is an Indian herb with aphrodisiac and adaptogenic effects. We’ve also seen claims that it’s a testosterone booster, but there isn’t any high-quality scientific evidence to back this up. (10)

Boron Citrate

Alongside Zinc and D-Aspartic Acid, this is our favorite ingredient in RSP Prime-T. It works similarly to DIM; balancing the ratio of testosterone and estrogen in your body.

Bioperine (Black Pepper Extract)

Bioperine won’t boost your testosterone; however, it helps with the bioavailability of other ingredients in RSP Prime T.

What’s Missing?

Although the Prime T formula is solid, it’s missing ingredients such as:

  • Indole-3-Carbinol – Top rated testosterone boosters typically include Indole-3-Carbinol in their formulas because it’s a strong anti-estrogen ingredient. (10, 12, 13) It’s a safer and more reliable option than DIM, which is synthetically isolated from I3C. IC3 is a completely natural compound that has shown on numerous occasions that it can reduce estrogen activity. (10, 12, 13) This is a good thing, because less estrogen means that testosterone has more freedom to build up in your system. You can read more about I3C vs DIM here
  • Vitamin B6 – This is a basic yet powerful addition to any testosterone booster. B6 boosts androgen production in testes, leading to higher T levels.

Another issue with RSP Prime T is that it uses below optimal doses of certain T-boosting compounds, including zinc and vitamin D. It’s definitely not a huge downside, but in this case, higher doses would offer better results.

Dosage Instructions

With RSP Prime-T, you’ll be taking 4 tablets of the product each night before bedtime. The supplement has 120 capsules, which means it’ll last you 30 days.

Usually, 1 serving per day is a good thing in most supplements. You pop a couple of pills all at once and let them do their thing. But with testosterone boosters, it’s more complicated.

See, the more daily servings a T booster has, the better. When you take multiple doses throughout the day, your body is getting a constant trickle of testosterone boosting nutrients. This has to be balanced with convenience and also food – many ingredients (fat soluble ones) are more readily absorbed with food so it can be better to co-incide intake with mealtimes.

On the other hand, when you take just 1 serving you’ll only get a short boost, and then what? Well, then your testosterone gets back to where it was.

This is ultimately the biggest downside of RSP Prime T.

It has a couple of great ingredients, but their delivery to your system isn’t optimal. How much will this affect your results? The only way to know is to take the supplement yourself, as everyone reacts differently.

Pros and Cons

RSP Prime-T deserves the credit for some of the great ingredients it has. This includes boron, zinc, and D-Aspartic Acid.

But it also has some major downsides that we cannot look past. The main problem with RSP Prime T is that it contains too few daily servings, which reduces its effects.

See for yourself:


  • Boron, Zinc, and D-Aspartic Acid all support healthy testosterone levels
  • Reasonable price (34-36 dollars for 30 servings)
  • Ingredients like Maca and Fenugreek Extract increase libido and sex drive


  • Just one serving per day, not enough to keep the T levels elevated for long
  • Contains a high dose of DIM, which in some studies has been shown to promote estrogen activity in the body
  • Underdosed zinc
  • Contains vitamins B12, B3, and folate, which aren’t useful for testosterone and muscle building unless you’re deficient in them.

RSP Prime-T Side Effects

Most users are happy with the effects of RSP Prime T and it doesn’t seem to cause any harmful side effects.

That said, RSP Prime T contains a high dose of DIM. Which, as we said, can make your body prefer estrogen over testosterone. The side effects of this could include:

  • Higher than normal estrogen levels
  • Weak libido
  • ‘Man boobs’
  • Belly fat

It’s a shame that RSP included such as high dose of DIM in their product. It would be a much more reliable supplement if they included a natural and more effective ingredient, such as Indole-3-Carbinol.

Customer Reviews

Most customer reviews on RSP Prime T say how they felt the effects, but they weren’t that strong. There are some users that were happy with the product, while others complained about side effects, or the lack of effects in general.

Let’s have a look at the reviews:

“Been using for three months. Not sure if it is just a placebo effect. But feel better after using. Always comes on time and as described.” – Philwalker76 (Amazon Customer)

I didn’t notice any difference at all. Took as recommended and didnt notice a thing. Not to mention these things are horse pills. They’re huge!” – John C Hargrove (Amazon Customer)

Helped a lot with sleep. I bought it to help with sleep as well as help with my sex drive. I don’t feel like it has helped with the sex drive part. But it does seem to help me recover faster from the gym which is kind of nice.” – David Smith (Amazon Customer)

It took roughly the whole bottle but I actually have started to feel effects. The only negative is that sometimes I wake up with a headache if I mix it with a multivitamin.” – SuperFly420 ( Customer)


1 bottle of RSP Prime T, which has 120 capsules, will cost you between $34-36. Since you should take 4 capsules per day, this means it will last you one month.

Is RSP Prime T Good Value For Money?

RSP Prime T is available on

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RSP Prime T has an attractive price tag – $36 dollars per bottle. However, we believe it’s not about how cheap the product is, it’s more important what kind of results you’ll get from it.

Based on what we’ve seen so far, RSP Prime T may help you with recovery from workouts, or give you a slight libido boost.

But with only 1 daily serving, underdosed zinc, and too high dose of DIM, it’s doesn’t seem strong enough to raise your T levels significantly.


RSP Prime T is certainly not a bad product, it’s produced by a reputable company and it uses some of the best natural T-boosting ingredients.

However, given the fact RSP Prime-T uses below optimal doses of zinc and vitamin D3, and has only 1 daily serving – its not as potent as it could be.

If you’re looking to get a slight boost in libido and perhaps enhanced muscle recovery, then RSP Prime T could be your answer.

But if you want a top-notch testosterone booster that will deliver reliable and strong results, then you may want to check your options before choosing RSP Prime T.

Our Top Testosterone Booster


  1. Effect of vitamin D supplementation on testosterone levels in men. (source)
  2. Nicotinic acid effects on insulin sensitivity and hepatic lipid metabolism: an in vivo to in vitro study. (source)
  3. Association of Vitamin B12 Deficiency with Fatigue and Depression after Lacunar Stroke.(source)
  4. Role of folic acid in nitric oxide bioavailability and vascular endothelial function. (source)
  5. Zinc status and serum testosterone levels of healthy adults. (source)
  6. The role and molecular mechanism of D-aspartic acid in the release and synthesis of LH and testosterone in humans and rats. (source)
  7. Effect of supplementation of traditional medicinal plants on blood glucose in non-insulin-dependent diabetics: a pilot study. (source)
  8. A double-blind, randomized, pilot dose-finding study of maca root (L. meyenii) for the management of SSRI-induced sexual dysfunction. (source)
  9. Ligand-independent activation of estrogen receptor function by 3, 3′-diindolylmethane in human breast cancer cells. (source)
  10. I3C vs DIM – Life Extension. (source)
  11. Aryl hydrocarbon receptor-mediated antiestrogenic and antitumorigenic activity of diindolylmethane. (source)
  12. Indole-3-carbinol is a negative regulator of estrogen receptor-alpha signaling in human tumor cells. (source)
  13. Indole-3-Carbinol disrupts estrogen receptor-alpha dependent expression of insulin-like growth factor-1 receptor and insulin receptor substrate-1 and proliferation of human breast cancer cells. (source)