D-Serine

D-Serine is an amino acid found in the brain. Derived from glycine, d-serine is a neuromodulator, meaning it regulates the activities of neurons.

D-Serine supplementation can reduce symptoms of cognitive decline. It is also able to reduce symptoms of diseases characterized by reduced N-methyl-D-aspartate (NMDA) signaling, which includes cocaine dependence and schizophrenia.

D-Serine’s effect on schizophrenia is well researched, and though it shows promise, it is also unreliable, since d-serine does not always reach the blood after supplementation. Sarcosine may be a more reliable treatment.

D-Serine is a coagonist at NDMA receptors, which means it improves the effects of other compounds that bind with the receptor. These compounds include glutamate and NMDA itself.

D-Serine is often categorized as a nootropic.

The usual dose used in D-serine studies is 30mg/kg of bodyweight. This correlates to an approximate dosage range of 2,045 – 2,727mg for people between 150 – 200 lbs. This dose appears to be the minimal effective dose for improving cognition in people suffering from a variety of diseases.

Preliminary evidence suggests that doubling or quadrupling the dosage to 60mg/kg and 120mg/kg, respectively, will cause additional benefits for people suffering from schizophrenia.

The Human Effect Matrix looks at human studies (it excludes animal and in vitro studies) to tell you what effects d-serine has on your body, and how strong these effects are.

Grade	Level of Evidence [show legend]
	Robust research conducted with repeated double-blind clinical trials
	Multiple studies where at least two are double-blind and placebo controlled
	Single double-blind study or multiple cohort studies
	Uncontrolled or observational studies only

Level of Evidence ? The amount of high quality evidence. The more evidence, the more we can trust the results.	Outcome	Magnitude of effect ? The direction and size of the supplement's impact on each outcome. Some supplements can have an increasing effect, others have a decreasing effect, and others have no effect.	Consistency of research results ? Scientific research does not always agree. HIGH or VERY HIGH means that most of the scientific research agrees.	Notes
	Cognition	Minor	High See all 3 studies	There may be an improvement in cognitive performance secondary to reducing symptoms of schizophrenia, and while there is mechanistic plausibility that this can also work in normal controls it has not yet been demonstrated
	Symptoms of Schizophrenia	Minor	Moderate See all 6 studies	D-Serine supplementation is able to reduce symptoms of schizophrenia (more efficacy on negative and cognitive symptoms rather than positive) in a dose-dependent manner between 30-120mg/kg, but possibly due to the unreliable increases in blood D-serine its benefits are also unreliable
	Anxiety	Minor	- See study	When taken 2 hours prior to testing, 2.1g D-serine seems effective in reducing anxiety during testing in otherwise healthy humans
	Attention	Minor	- See study	There was an increase in sustained attention during cognitive testing in otherwise healthy subjects given 2.1g D-serine prior to testing, as assessed by CPT-IP.
	Subjective Well-Being	Minor	- See study	Reported sadness during cognitive testing appears to be reduced with D-serine supplementation when compared to placebo
	Symptoms of Parkinson's Disease	Minor	- See study	Preliminary evidence suggests that the standard dosage of D-Serine can alleviate some symptoms of Parkinson's disease
	Symptoms of Post-Traumatic Stress Disorder	Minor	- See study	One study using 20mg/kg D-serine in subjects with PTSD noted benefits with supplementation when compared to placebo.
	Working Memory	Minor	- See study	Immediate recall appears to be increased from D-serine when 2.1g is supplemented 2 hours prior to testing.
	Reaction Time	-	- See study	When 2.1g D-serine is taken two hours prior to cognitive testing, there does not appear to be an increase in reaction time when compared to placebo
	Serum BDNF	-	- See study	2.1g D-serine in otherwise healthy humans does not acutely influence serum BDNF concentrations
	Verbal Fluency	-	- See study	In a category fluency test, 2.1g D-serine taken two hours earlier appears to improve fluency. The increase was larger than seen with placebo, but comparing the two groups did not yield a significant benefit with D-serine over placebo statistically