In jyotiṣa there is a saying that when Jupiter protects there is none that can destroy. Jupiter brings in the great mantra powers into the fifth bhāva and dharma into the ninth bhāva. He is the ‘jīva graha’ responsible for bringing life into the various bodies. The Brahma Yamala lists various navagraha kavacha (protection) stotra which have the best eighteen names of each of the graha.

श्रीगणेशाय नमः।

अस्य श्रीबृहस्पतिकवचस्तोत्रमन्त्रस्य
ईश्वर ऋषिः,
अनुष्टुप् छन्दः,
गुरुर्देवता,
गं बीजं,
श्रीशक्तिः,
क्लीं कीलकं,
गुरुप्रीत्यर्थं जपे विनियोगः।

अभीष्टफलदं देवं सर्वज्ञं सुरपूजितम्।
अक्षमालाधरं शान्तं प्रणमामि बृहस्पतिम्॥ १॥

बृहस्पतिः शिरः पातु ललाटं पातु मे गुरुः।
कर्णौ सुरगुरुः पातु नेत्रे मेऽभीष्टदायकः॥ २॥

जिह्वां पातु सुराचार्यो नासां मे वेदपारगः।
मुखं मे पातु सर्वज्ञो कण्ठं मे देवतागुरुः॥ ३॥

भुजावाङ्गिरसः पातु करौ पातु शुभप्रदः।
स्तनौ मे पातु वागीशः कुक्षिं मे शुभलक्षणः॥ ४॥

नाभिं देवगुरुः पातु मध्यं पातु सुखप्रदः।
कटिं पातु जगद्वन्द्य ऊरू मे पातु वाक्पतिः॥ ५॥

जानुजङ्घे सुराचार्यो पादौ विश्वात्मकस्तथा।
अन्यानि यानि चाङ्गानि रक्षेन्मे सर्वतो गुरुः॥ ६॥

इत्येतत्कवचं दिव्यं त्रिसन्ध्यं यः पठेन्नरः।
सर्वान्कामानवाप्नोति सर्वत्र विजयी भवेत्॥ ७॥

॥ इति श्रीब्रह्मयामलोक्तं बृहस्पतिकवचं सम्पूर्णम्॥

śrīgaṇeśāya namaḥ |

asya śrībṛhaspatikavacastotramantrasya
īśvara ṛṣiḥ,
anuṣṭup chandaḥ,
gururdevatā,
gaṁ bījaṁ,
śrīśaktiḥ,
klīṁ kīlakaṁ,
guruprītyarthaṁ jape viniyogaḥ |

abhīṣṭaphaladaṁ devaṁ sarvajñaṁ surapūjitam |
akṣamālādharaṁ śāntaṁ praṇamāmi bṛhaspatim || 1||

bṛhaspatiḥ śiraḥ pātu lalāṭaṁ pātu me guruḥ |
karṇau suraguruḥ pātu netre me’bhīṣṭadāyakaḥ || 2||

jihvāṁ pātu surācāryo nāsāṁ me vedapāragaḥ |
mukhaṁ me pātu sarvajño kaṇṭhaṁ me devatāguruḥ || 3||

bhujāvāṅgirasaḥ pātu karau pātu śubhapradaḥ |
stanau me pātu vāgīśaḥ kukṣiṁ me śubhalakṣaṇaḥ || 4||

nābhiṁ devaguruḥ pātu madhyaṁ pātu sukhapradaḥ |
kaṭiṁ pātu jagadvandya ūrū me pātu vākpatiḥ || 5||

jānujaṅghe surācāryo pādau viśvātmakastathā |
anyāni yāni cāṅgāni rakṣenme sarvato guruḥ || 6||

ityetatkavacaṁ divyaṁ trisandhyaṁ yaḥ paṭhennaraḥ |
sarvānkāmānavāpnoti sarvatra vijayī bhavet || 7||

|| iti śrībrahmayāmaloktaṁ bṛhaspatikavacaṁ sampūrṇam ||

guru
The eighteen names of Jupiter relate to eighteen body parts starting from the top of head (śiras). One method uses this formula: Each name associates with two drekkāṇa reckoned from lagna in the horoscope.

1 bṛhaspati
2 guru
3 suraguru
4 abhīṣṭadāyaka
5 surācārya
6 vedapāraga
7 sarvajña
8 devatāguru
9 aṅgirāsa
10 śubhaprada
11 vāgīśa
12 śubhalakṣaṇa
13 devaguru
14 sukhaprada
15 jagadvandya
16 vākpati
17 surācāryo
18 viśvātma

However, the stotra clearly spells out the importance of the second name ‘guru’ as this can be used all the time to protect every part. The simple mantra for protection from all evils is
ॐ गुरवे नमः | om gurave namaḥ

Illustration: Lagna 14° Pisces is in 2nd drekkāṇa – start count from here
Jupiter in 26° Pisces = 3rd drekkāṇa of Pisces
Counting from Lagna to Jupiter we have ‘2’ or Jupiter is in 2nd drekkāṇa. The name obtained from the list is the first name ‘bṛhaspati’. Native should do the mantra
ॐ गां श्रीं क्लीं बृहस्पतये नमः
om gāṁ śrīṁ klīṁ bṛhaspataye namaḥ

In our tradition we use the gaM bīja for Ganesa and gaaM for Guru and Gita.