[8] Levmetamfetamine is significantly less potent in terms of physiologic and subjective drug effects than racemic methamphetamine, dextromethamphetamine, and related amphetamines, especially when used as a nasal decongestant at therapeutic doses.

[12][16][18][4] The potencies of levmetamfetamine, levoamphetamine, dextromethamphetamine, and dextroamphetamine in terms of norepinephrine release in vitro and in vivo in rats are all similar.

[20][19][22] In accordance with the findings of catecholamine release studies, levmetamfetamine is 2- to 10-fold or more less potent than dextromethamphetamine in terms of psychostimulant-like effects in rodents.

[2][25][27][4][22] In clinical studies, levmetamfetamine at oral doses of 1 to 10 mg has been found not to affect subjective drug responses, heart rate, blood pressure, core temperature, electrocardiography, respiration rate, oxygen saturation, or other clinical parameters.

[2][3] However, higher doses of levmetamfetamine, for instance 0.25 to 0.5 mg/kg (mean doses of ~18–37 mg) intravenously, have been reported to produce significant pharmacological effects, including increased heart rate and blood pressure, increased respiration rate, and subjective effects like intoxication and drug liking.

[2][4] On the other hand, in contrast to dextromethamphetamine, levmetamfetamine also produces subjective "bad" or aversive drug effects.

[28] For comparison to levmetamfetamine, 5 to 60 mg oral doses of the related drug levoamphetamine have been used clinically and have been reported to produce significant pharmacological effects, for instance on wakefulness and mood.

[2] Racemic methamphetamine contains two optical isomers in equal amounts, dextromethamphetamine (the dextrorotatory enantiomer) and levmetamfetamine.

[2] Levmetamfetamine can register on urine drug tests as either methamphetamine, amphetamine, or both, depending on the subject's metabolism and dosage.

[49][50] In 1998, the United States Food and Drug Administration (FDA) required that the chemical name on the labeling be changed from l-desoxyephedrine to levmetamfetamine.

The most recent change in Food and Drug Administration regulations for levmetamfetamine inhalers was in 1994, with the adoption of a final monograph.