What are the Differences Between 1P-LSD and LSD-25?

In this article, we discuss the variations between LSD-25, the “original” form of LSD, and a similar hallucinogenic called 1P-LSD.

1P-LSD has become a popular alternative to LSD-25 since its introduction in 2015, leading many psychedelic users to question the differences between 1P-LSD and LSD-25 in terms of dosage, effects, and overall experience.

Both LSD-25 and 1P-LSD are derivatives of lysergic acid. 1 Chemically, these substances are analogs, meaning that they share the same structure save for a single component. Due to these structural similarities, both are capable of acting on the central nervous system to produce hallucinogenic effects.

You don't drive with your eyes closed.

It's always a good idea to test your substance before using it. Buy reagent tests at Elevation Chemicals. Learn more about reagent testing for LSD and its analogs here at Explore Psychedelics.

The History and Legality of 1P-LSD

1P-LSD, like LSD-25, is illegal to consume. However, 1P-LSD is legal to purchase for “research purposes” and became available online in 2015 as a research chemical labeled “not for human consumption”. It is not known who discovered 1P-LSD, but it was likely produced for the first time in an academic setting.2

Since the intention of a 1P-LSD purchase does not need to be verified, it is much easier to obtain without risk than LSD-25. However, its lack of status as an officially controlled substance makes the legality of 1P-LSD a grey area.

Reagent Tests

While reagent tests such as Ehrlich, Marquis, and Mecke can help to distinguish LSD and its analogs from other substances, these reagents cannot be used to detect differences between analogs such as LSD-25 and 1P-LSD.3 The best way to determine whether a substance is LSD-25 or 1P-LSD is to send a sample to a lab like Energy Control for testing.4

Dosing Relative to LSD-25

No official studies have been performed comparing the effects of 1P-LSD and LSD-25 while controlling for dose, but data gathered from personal experiences suggests that identical dosing of 1P-LSD and LSD-25 will create comparable effects.

Some users claim that, while similar, they experience 1P-LSD differently than LSD-25. For example, a study which gathered and analyzed results from an anonymous online survey cataloged the differences in user experience between LSD and its analogs. Overall, LSD analogs such as 1P-LSD were ranked weaker than LSD-25 in strength, pleasurable high, and comedown. On the other hand, users reported similarities in duration and peak time.5

It is important to note that this summary of experiences is entirely anecdotal and self-reported, and few peer-reviewed research studies have been performed in a controlled laboratory setting to document the pharmacological effects of 1P-LSD.

According to one 2015 study, 1P-LSD had only 38% of the potency6 of LSD-25 when injected into male mice.7 However, 1P-LSD still activated serotonin receptors in the brains of these mice, suggesting that 1P-LSD acts in the same way as LSD-25. While the effects of 1P-LSD have not been studied directly in humans, the study did incubate 1P-LSD in human serum (a derivative of human blood plasma) and found that LSD-25 was detectable in the serum after a number of exposure times. Since human serum is a much more accurate assessment of a drug’s activity in the human body than animal serum8, these results suggest that 1P-LSD is a prodrug to LSD-25. In other words, the human body likely converts 1P-LSD to LSD-25.

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  1. The only chemical difference between LSD-25 and 1P-LSD is that 1P-LSD has a propionyl group bound to the nitrogen in its indole ring. 

  2. PsychonautWiki 

  3. DMT Nexus Forum 

  4. Energy Control analyzes samples by pairing gas and liquid chromatography with mass spectrometer techniques. With these strategies, Energy Control’s drug testing services can detect both the substances present in a compound and quantify these substances via a percentage. 

  5. Genie in a blotter: A comparative study of LSD and LSD analogues’ effects and user profile. 

  6. This percentage was determined by measuring which mice demonstrated a head-twitch response, a common feature frequently observed after doses of LSD and other substances which activate serotonin receptors. 

  7. Return of the lysergamides. Part I: Analytical and behavioural characterization of 1‐propionyl‐d‐lysergic acid diethylamide (1P‐LSD) 

  8. Biocompare