Black spruce (Picea mariana) essential oil is sometimes used in traditional and folk medicine for supporting the adrenal cortex and promoting general vitality. The primary basis for this use is anecdotal and rooted in the practices of aromatherapy and herbal medicine, particularly in Europe and North America. Practitioners claim that inhaling black spruce essential oil or applying it topically (diluted) can help combat fatigue and stress, which are often associated with adrenal function. The rationale is that the invigorating scent and purported adaptogenic properties may stimulate and "revitalize" the adrenal glands, although the exact mechanisms are not defined in traditional texts.

However, there is little to no scientific research directly linking black spruce—either as an herb or as an essential oil—to measurable effects on adrenal gland function or cortisol regulation. Most evidence is indirect, relating only to the general effects of essential oils on mood or perceived stress. Thus, while black spruce is used traditionally for adrenal support, these uses are not substantiated by rigorous clinical trials or pharmacological studies. Its inclusion in adrenal support protocols is therefore best categorized as traditional, with limited evidence.