I have seen 1.5Hz being linked to HGH, but also 4 or 5 other frequencies as well, so it’s difficult to know what may work if any. I haven’t seen any research relating to HGH and brainwave entrainment. It’s widely believed that 40Hz is the limit for achieving a brainwave entrainment effect, which is also where many believe the gamma frequency range begins. Once you get over 40Hz into gamma your brainwave activity isn’t likely to stay in sync with it. So from a brainwave entrainment perspective, I recommend high beta frequencies for increasing energy during workouts.
No worries. For meditation, you should use low Theta state recordings – Theta is between 4-8Hz. To learn a bit more about this type of brainwave meditation, I recommend you read this guide that comes with two free samples: https://www.binauralbeatsmeditation.com/free-mp3/ This company also do a very good Deep Meditation recording which you can find at this link: https://www.binauralbeatsmeditation.com/product/deep-meditation/
This session uses a proven technique for inducing deep relaxation, playing one frequency for two minutes, then alternating to a second after a 30-second ramp, then reversing the process. The first half of the session switches between a serotonin-boosting 10Hz and the grounding and rejuvenating 7.83Hz Schumann resonance. The second half of the session goes even deeper, alternating between the relaxing 7.83Hz and 6.3Hz, a frequency associated with releasing anger and irritability. The session ends on a chilled out 10Hz.