Dorian Yates Testoboost – Grape 270g

Tribulus and 'testosterone' herbs· evidence: Insufficient

Tribulus terrestris, maca, Siberian ginseng, wild yam, fenugreek and similar herbs are common in products marketed for testosterone. Reviews of tribulus find it does not raise testosterone in healthy men, and the evidence for the others is small or absent. Wild yam contains diosgenin, which the body cannot turn into hormones.

There are no authorised health claims for these herbs, so we make no claims about what they do. Sleep, enough calories and protein, resistance training and a healthy weight are what affect testosterone; if you are worried about low levels, ask your GP for a blood test.

Typical dose: Varies widely by product; check the label.

Safety: Not for under-18s, or in pregnancy or breastfeeding. Tribulus may affect blood sugar and blood pressure; Siberian ginseng may interact with blood thinners, diabetes medicines and digoxin. Speak to your GP first if you take regular medication. Sports users should choose batch-tested products.

Research we looked at:
Qureshi A, Naughton DP, Petroczi A (2014). A systematic review on the herbal extract Tribulus terrestris and the roots of its putative aphrodisiac and performance enhancing effect. Journal of Dietary Supplements 11(1):64-79.
Pokrywka A et al. (2014). Insights into supplements with Tribulus terrestris used by athletes. Journal of Human Kinetics 41:99-105.

D-aspartic acid· evidence: Insufficient

D-aspartic acid (DAA) is an amino acid involved in hormone signalling. It became popular as a testosterone booster after one small study, but later trials in men who train found no meaningful rise in testosterone or gains in strength, and one found a drop at 6 g a day.

There are no authorised health claims for D-aspartic acid, so we make no claims about what it does. If you are worried about low testosterone, a simple blood test through your GP is the way to find out.

Typical dose: Products typically give 2 to 3 g a day.

Safety: Not for under-18s, or in pregnancy or breastfeeding. Long-term safety data are limited. Speak to your GP first if you take regular medication or have a hormone-related condition.

Research we looked at:
Roshanzamir F, Safavi SM (2017). The putative effects of D-aspartic acid on blood testosterone levels: a systematic review. International Journal of Reproductive BioMedicine 15(1):1-10.
Melville GW, Siegler JC, Marshall PW (2015). Three and six grams supplementation of D-aspartic acid in resistance trained men. Journal of the International Society of Sports Nutrition 12:15.

Caffeine· evidence: Strong

Caffeine is one of the best-supported performance aids, with consistent research showing it can improve endurance, strength and alertness. The doses used in research are usually 3–6 mg per kg of body weight, taken about an hour before exercise.

The catch is the dose: it adds to any coffee, tea or energy drinks you already have, and it can disrupt sleep if taken later in the day. There is no authorised health claim for caffeine and sports performance in the UK.

Typical dose: Research doses are 3–6 mg per kg of body weight

Safety: High caffeine content. Not recommended for children or pregnant or breastfeeding women. Healthy adults should keep total caffeine from all sources to no more than 400 mg a day and 200 mg at a time. Avoid late in the day and do not combine with other caffeine products.

Research we looked at:
Guest NS et al. (2021). International Society of Sports Nutrition position stand: caffeine and exercise performance. J Int Soc Sports Nutr 18:1.
EFSA NDA Panel (2015). Scientific opinion on the safety of caffeine. EFSA Journal 13(5):4102.

Beta-alanine· evidence: Moderate

Beta-alanine raises carnosine levels in muscle, which helps buffer acid during hard effort. Reviews of the research find a small benefit in high-intensity efforts lasting roughly one to four minutes, such as hard intervals or rowing sprints. It does little for single heavy lifts or for long, steady exercise.

It works by building up over weeks, so it needs about 3–6 g a day for at least two to four weeks. Many combined products contain far less than that. There is no authorised health claim for beta-alanine.

Typical dose: 3.2–6.4 g a day, split into smaller doses, for at least 2–4 weeks

Safety: Commonly causes a harmless tingling or pins-and-needles feeling on the skin (paraesthesia), which is stronger with larger single doses.

Research we looked at:
Trexler ET et al. (2015). International Society of Sports Nutrition position stand: beta-alanine. J Int Soc Sports Nutr 12:30.

Cost per daily dose lets you compare packs of different sizes fairly.Worked out from our current prices.