What to Combine GABA With

GABA is often part of "evening" complexes together with L-theanine, magnesium, melatonin, and herbal extracts. Athletes add it to a protein shake before sleep. Which of these combinations have a scientific basis, which are just marketing, and which should be avoided? The editorial team has sorted GABA combinations by level of justification and safety.

How to evaluate combinations with GABA

To evaluate any combination with GABA, the editorial team uses three questions. First: is there research on the combination itself, not just the individual components? Second: do the components enhance the same effect — for example, sedation or lowering of pressure? Third: does one substance interfere with achieving the goal of another?

The main known effects of GABA as a supplement are possible easing of falling asleep, a moderate effect on stress measures, and the ability to lower blood pressure. It is precisely these effects that determine what its combination is logical with and what it is risky with.

There are few studies that examined GABA in combinations. Most "synergistic" formulas on the market are composed on the principle that "each component separately has some data," not on the basis of clinical trials of the mixture itself. This does not make them harmful, but it should be understood: the effect of the complex is unknown.

The practical rule is to introduce new components one at a time, with an interval of a few days. That makes it easier to understand what exactly helps or causes adverse reactions, and to avoid a situation where a person takes five sleep aids without knowing which of them works.

GABA and L-theanine

L-theanine is an amino acid from tea leaves associated with a state of calm focus. A randomized study by Hidese et al. (2019) in healthy adults showed improvement in certain stress and sleep measures with L-theanine. Therefore combining theanine with GABA in evening formulas looks logical.

The combination of GABA and L-theanine itself was studied, in particular, in the work by Kim et al. (2019). In that animal study, a mixture of the two substances shortened sleep latency and affected the structure of non-REM sleep more strongly than each component separately. This is an interesting result, but transferring data from animals to humans requires separate clinical studies.

From a safety standpoint the combination looks acceptable: both substances at typical doses are well tolerated, and pronounced sedation is not characteristic of theanine. However, total drowsiness in sensitive people is possible, so it is better to take the combination for the first time in the evening, when you do not need to get behind the wheel.

For athletes who train in the evening and fall asleep poorly after exercise, the pair "GABA + theanine" can be a first experiment instead of complex multi-component formulas. If there is no effect within 2–3 weeks, there is no sense in continuing.

Magnesium, melatonin, and other sleep aids

Magnesium.Magnesium is involved in the work of the nervous and muscular systems, and in athletes with intense sweating insufficient intake is not uncommon. In the study by Abbasi et al. (2012) in elderly people with insomnia, magnesium improved certain sleep measures. The mechanisms of action of magnesium and GABA are different, no direct interactions have been described, so the combination is considered acceptable.

Melatonin.Melatonin works best for circadian rhythm disorders — a change of time zones, a shifted schedule. A meta-analysis by Ferracioli-Oda et al. (2013) showed a moderate reduction in the time to fall asleep in primary sleep disorders. Combining it with GABA is not prohibited, but the advisability depends on the cause of poor sleep; both agents at once complicate the assessment of the effect.

Herbal sedatives.Valerian, passionflower, hops, and lemon balm are often part of the same complexes. Each of them can add drowsiness. Combined with GABA, this can lead to morning grogginess, which matters for those who train in the morning or drive.

5-HTP.Some "mood and sleep complexes" combine GABA with 5-HTP. There is no known direct interaction between them, but 5-HTP itself has serious restrictions when combined with antidepressants and other serotonergic agents. For such a combination it is important to take the risks of 5-HTP into account.

• logical: GABA + L-theanine, GABA + magnesium;
• acceptable with an assessment of advisability: GABA + melatonin;
• with caution: GABA + several herbal sedatives at once;
• taking medications into account: complexes with GABA and 5-HTP.

GABA and sports nutrition

Whey protein.This is probably the most studied GABA combination in a sports context. In the 12-week study by Sakashita et al. (2019), men who combined strength training with 10 g of whey protein and 100 mg of GABA demonstrated a greater gain in lean mass than those who took protein alone. The result of one small study requires confirmation, but the combination is safe and convenient — for example, in an evening shake.

Creatine monohydrate.Creatine is one of the most studied supplements for strength sports, which is confirmed by the position statement of the International Society of Sports Nutrition (Kreider et al., 2017). Its mechanism of action — energy metabolism in muscles — does not overlap with GABA, and no interactions have been described.

Caffeine and pre-workout complexes.There is no direct dangerous interaction, but combining them in a single dose is contradictory: caffeine stimulates, GABA relaxes. Using GABA to "extinguish" late caffeine is irrational; it is simpler to move stimulant intake to earlier hours.

Carbohydrates, electrolytes, vitamins.The ordinary components of an athlete's diet do not conflict with GABA. Vitamin B6, which is sometimes added "for GABA synthesis," is useful in deficiency, but excess doses beyond need provide no additional effect.

Combinations to avoid

Alcohol.Alcohol acts, in particular, through GABA-A receptors and has a pronounced sedative action. Although the GABA supplement probably enters the brain to a limited extent, combining it with alcohol makes no sense and potentially intensifies grogginess. Moreover, alcohol itself worsens sleep quality and recovery.

Sleeping pills and sedatives.Benzodiazepines, Z-hypnotics, barbiturates, gabapentinoids, baclofen, first-generation antihistamines — all of them depress the central nervous system. GABA should not be added to them without coordination with a doctor.

Blood-pressure medications.GABA can lower blood pressure; this effect was shown, in particular, in the study with fermented milk in people with mild hypertension (Inoue et al., 2003). In combination with antihypertensive drugs, dizziness and orthostatic reactions are possible.

Antiepileptic drugs.Many of them act on the GABAergic system, and the doctor carefully selects their dose. Any supplements claiming an effect on this system should be discussed with a neurologist.

Products with phenibut.Combining GABA with phenibut or taking "complexes" containing it carries the risks of phenibut: tolerance, dependence, severe withdrawal syndrome. Check the composition of each product in the combination.

Editorial conclusions

The most logical combinations of GABA are with L-theanine and magnesium to support falling asleep, and with whey protein in an evening dose. Creatine and basic sports nutrition are compatible with GABA.

Melatonin and herbal sedatives can be combined with GABA, but this complicates the assessment of the effect and increases the risk of morning drowsiness.

You should avoid combining it with alcohol, sleeping pills, sedatives, and antiepileptic drugs, and with blood-pressure medications — only under a doctor's supervision.

We also recommend reading our materials "How to Take GABA: Dosage, Timing, Duration," "Side Effects of GABA," and "What to Combine 5-HTP With."

References

1. Kim S, Jo K, Hong KB, Han SH, Suh HJ. GABA and l-theanine mixture decreases sleep latency and improves NREM sleep. Pharm Biol. 2019;57(1):65–73.
2. Hidese S, Ogawa S, Ota M, et al. Effects of L-theanine administration on stress-related symptoms and cognitive functions in healthy adults: a randomized controlled trial. Nutrients. 2019;11(10):2362.
3. Sakashita M, Nakamura U, Horie N, et al. Oral supplementation using gamma-aminobutyric acid and whey protein improves whole body fat-free mass in men after resistance training. J Clin Med Res. 2019;11(6):428–434.
4. Abbasi B, Kimiagar M, Sadeghniiat K, et al. The effect of magnesium supplementation on primary insomnia in elderly: a double-blind placebo-controlled clinical trial. J Res Med Sci. 2012;17(12):1161–1169.
5. Ferracioli-Oda E, Qawasmi A, Bloch MH. Meta-analysis: melatonin for the treatment of primary sleep disorders. PLoS One. 2013;8(5):e63773.
6. Kreider RB, Kalman DS, Antonio J, et al. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. J Int Soc Sports Nutr. 2017;14:18.
7. Inoue K, Shirai T, Ochiai H, et al. Blood-pressure-lowering effect of a novel fermented milk containing gamma-aminobutyric acid (GABA) in mild hypertensives. Eur J Clin Nutr. 2003;57(3):490–495.
8. Oketch-Rabah HA, Madden EF, Roe AL, Betz JM. United States Pharmacopeia (USP) safety review of gamma-aminobutyric acid (GABA). Nutrients. 2021;13(8):2742.